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**rookiepber** · June 19th, 01:37 AM

I was hoping i could borrow a local cops chronograph, i think that's what it's called...but how to you conver mph to fps, and do you think the chron will just have fps on there?

***MedicDVG*** · June 19th, 01:50 AM

AS I explained in your identical post in a different thread:

1 mile/hr is 5280 feet in 1 hour, or 5280 feet in 3600 seconds.
That boils down to around 1.46 feet/second.

so 290 feet per second would translate out to the following equation

290 feet | 1 mile | 60 sec | 60 Min
-------------------------------------------------- = Miles/hours
1 sec | 5280 feet | 1 min | 1 hr

Cancel your units, and you get 290 X 60 X 60 / 5280 = 197.7 Miles/hour

So a ball traveling 290 fps = roughly 198 mph

Make sense?

Now doing it the other way (Mph to fps)

198 Miles | 5280 Feet | 1 hr | 1 min
----------------------------------------------- = feet/sec
1 hour | 1 mile | 60 min | 60 sec

cancel you units and the equation is 198 X 5280 / 60 X 60 = 290.4 feet / sec

**Aggression** · June 19th, 10:06 AM

holy crap I didnt know they traveld that fast! Thanks med

**The nforcer2006** · June 19th, 11:39 AM

i did a conversion on my phone and for 280 its comes out to be 98 mph.

Rebel Yell · June 19th, 12:08 PM

I don't think a radar gun is gonna pick up a paintball

***MedicDVG*** · June 19th, 01:04 PM

Quote:

Originally posted by Rebel Yell
I don't think a radar gun is gonna pick up a paintball

What do you think a chronograph is??? Its not a little magic box filled with happy paintball fairies carrying stopwatches.

***MedicDVG*** · June 19th, 01:08 PM

Quote:

Originally posted by The nforcer2006
i did a conversion on my phone and for 280 its comes out to be 98 mph.

Hmm that seems awful slow: I think you have a error in your conversion factor or something -- Lets review!

280 feet | 60 sec | 60 min | 1 mile
-------------------------------------------------- = miles/hour
1 sec | 1 min | 1 hour | 5280 feet

or

280 X 60 X 60 / 5280 = 190.9 miles / hr

hmmm... nope it still comes out 191 mph. No wonder they hurt.

Now for fun, somebody weigh a few paintballs to get the "average" weight and we can determine the amount of energy depositied to your pink butt when shot with a paintball traveling at 191 mph! Whee!

**WyrmMaster** · June 19th, 03:47 PM

Quote:

Originally posted by MedicDVG
What do you think a chronograph is??? Its not a little magic box filled with happy paintball fairies carrying stopwatches.

true, but a chrono is designed to pick up a fast moving .68 caliber object. A cops radar gun is designed to give the speed of a car. Big difference in how they might be designed, even though they operate on exactly the same principle.

**PaintWizard** · June 19th, 03:56 PM

y=x(60)(60)/5280

y=mph
x=fps

-Jon

***MedicDVG*** · June 19th, 07:12 PM

Quote:

Originally posted by PaintWizard
y=x(60)(60)/5280

y=mph
x=fps

-Jon

Oh sure... use ALgebra.. woo hoo look at me I am mr. super math!! Woot! LOL!

I used dimensional analysis as it works so very well to show the logic behind the equation. I could never just plug in variables and solve.

Oh well..

**PaintWizard** · June 19th, 07:24 PM

Quote:

Originally posted by MedicDVG
Oh sure... use ALgebra.. woo hoo look at me I am mr. super math!! Woot! LOL!

I used dimensional analysis as it works so very well to show the logic behind the equation. I could never just plug in variables and solve.

Oh well..

Your method seemed a lot more confusing. I thought I would simplify.

-Jon

**The nforcer2006** · June 20th, 11:21 AM

whoops sorry, it does come out to 191, i was missing a digit.

**jpm091982** · July 12th, 05:56 PM

maybe that's why that one tore my shirt and broke my skin when I got nailed at about six or seven feet ?????? ouch, d**g it

**LookOverThere** · July 12th, 06:10 PM

Theres a 10 FT Rule at my field, THe refs screma TEN FOOT RULE TEN FOOT RULE when some1 gets in that range.

**MrHanky04** · July 12th, 06:20 PM

i was watching popular mechanics for kids a while back, they said that a cop chrono uses a radio beam or something that shoots to the car's engine and then the beam bounces back to the chrono or something... and thats how it works. but i dont know, those kids on popular mechanics are pretty darn crazy

**HP_lovecraft** · July 12th, 07:55 PM

Quote:

Originally Posted by PaintWizard

y=x(60)(60)/5280

That looks right.
BTW, paintballs don't have much energy compared to bullets.

Yes, a .68 PAINTBALL does travel at 300fps, and plenty of "lethal" bullets travel at 500fps, but the bullet is obviously much more heavy, and therefore has much more energy.

paintball: 10 lbs of force
.17 pellets: 15 lbs of force
38-special: 250 lbs of force
45 ACP: 356 lbs of force
9MM: 380 lbs of force
454 Casull: 1000 lbs of force
etc

-Nick

***MedicDVG*** · July 12th, 10:48 PM

Someday I want to be as smart as Nick.....

BushmasterMAN · July 13th, 01:27 AM

it's summer time...I don't understand the math in this thread.

Jamo_asleep · July 13th, 09:27 AM

a police radar is the same as any other radar, it throws a radio wave, and how ever long it takes to hit the object and get back to the radar is how fast it is moving. u would just have to set the radar to fps, mph, kph w/e u want it at

**jpm091982** · July 14th, 08:43 PM

I don't happen to play at a 'field' - just me and my buddies. trying to see who can inflict the most damage...........